WASHINGTON — Federal mediators are entering the stalled NHL labor talks, with the season’s first 2½ months already lost because of the lockout.

George Cohen, director of the Federal Mediation and Conciliation Service, said Monday the parties had agreed to use the agency. He assigned three mediators to assist in negotiations — deputy director Scot Beckenbaugh, director of mediation services John Sweeney and Commissioner Guy Serota.

“While we have no particular level of expectation going into this process, we welcome a new approach in trying to reach a resolution of the ongoing labor dispute at the earliest possible date,” NHL deputy commissioner Bill Daly said.

Cohen has worked with the players’ associations for Major League Baseball, helping end the 1994-95 strike as an outside counsel, and the NBA. He was an adviser to the NHL players’ union before joining the FMCS three years ago.

Cohen mediated during the 2010 negotiations in Major League Soccer and 2011 talks in the NFL and NBA, along with this year’s dispute between the NFL and its on-field officials.

Hockey players and management have not negotiated since last Wednesday. The NHL has canceled more than one-third of its regular season, including all games through Dec. 14, the New Year’s Day outdoor Winter Classic and the All-Star weekend scheduled for Jan. 26-27 at Columbus, Ohio.

“I have had separate, informal discussions with the key representatives of the National Hockey League and the National Hockey League Players’ Association during the course of their negotiations for a successor collective bargaining agreement,” Cohen said in a statement.

“Due to the extreme sensitivity of these negotiations and consistent with the FMCS’s longstanding practice, the agency will refrain from any public comment concerning the future schedule and/or the status of the negotiations until further notice.”